1. Field of the Invention
The present invention relates generally to substrate drying technology and, more particularly, to a method and apparatus for removing liquid from semiconductor wafer surfaces under manufacture.
2. Description of the Related Art
The manufacturing of semiconductor devices (e.g., integrated circuits or flat panel displays) typically involves subjecting a substrate (e.g., a semiconductor wafer or glass flat panel) to a series of thin layer formation, patterning, ion implantation and liquid-based processes. Consequently, it is often necessary to remove liquids from surfaces of the substrate following the liquid-based processes (e.g., liquid-based cleaning, scrubbing, and rinsing processes). Such liquid removal processes are referred to as “drying” processes and the associated apparatus typically referred to as “dryers.”
Conventional drying methods and apparatus include (a) spin-rinser methods and apparatus wherein a substrate is rinsed with a liquid (e.g., water) and then spun at a high speed to remove liquid from its surfaces; (b) isopropyl alcohol (IPA) vapor methods and apparatus wherein IPA vapor is employed to displace the liquid and then is itself evaporated from the surfaces and (c) Marangoni methods and apparatus wherein a solvent meniscus is used to displace liquid from substrate surfaces.
Conventional methods and apparatus for removing liquid can leave residue, which was dissolved in the liquid, behind on the surfaces of the substrate. The presence of such residue on the substrate surface is commonly referred to in the field as a “water mark.” These water marks are believed to include various silicon-based solid materials such as silicon dioxide (SiO2). Water marks are created due to the presence of silicon elements from the substrate which have been dissolved in liquid drops and appear after removal of the liquid drops from the surface of the substrate.
Conventional drying methods and apparatus can be expensive to purchase, operate and maintain. Furthermore, the use of solvents (e.g., IPA) in many conventional drying methods and apparatus presents an environmental problem in terms of emission control and disposal.
Still needed in the field, therefore, are a method and apparatus for quickly removing liquid from surfaces of a substrate (e.g., a semiconductor wafer) without leaving behind substantial residue (e.g., water marks). In addition, the method and apparatus should be cost effective and environmentally sound.